Just bought the engine after playing GoF years ago on another PC, before the Maelstrom Engine. I installed Eras 2 but I can't play it because the mouse keeps running around the screen so that menus are unusable. Any help?

Yours is the only report of mouse drifting that I have heard about.  I can't reproduce this myself, so I am not sure what the problem might be.  If you are on the main game menu, can you try using the up/down arrow keys to switch the selected menu option?  Does that happen to stop the mouse drift if you try that, or does the mouse drifting continue?